In general, in order to protect a driver and an occupant at the time of a vehicle collision, airbag modules are used by being mounted in a steering handle and an instrument panel.
The airbag module deploys an airbag at the time of a vehicle collision so as to prevent the driver or the occupant from colliding with a crash pad or a wind shield that are provided in a vehicle, thereby reducing injury due to a collision.
The airbag module includes an airbag housing cover, an inflator which generates gas at the time of a vehicle collision, an airbag which is deployed by gas generated by the inflator, a separate detection sensor, and an electronic control module which explodes a detonator of the inflator.
The inflator includes the detonator which is ignited by an operational control signal that is output from the electronic control module, and a gas generation body which generates gas as the detonator is ignited.
According to the general airbag module that is configured as described above, when a traveling speed is rapidly decreased due to a head-on collision, an impact sensor detects the decrease in traveling speed and generates a preset signal, and the electronic control module, which recognizes an impact signal output from the impact sensor, ignites the detonator so as to combust the gas generation body.
In this case, the airbag is rapidly expanded and deployed because the gas generation body rapidly generates gas, the deployed airbag cushion prevents the head and chest of the occupant from being moved toward a front side of the vehicle by inertia so as to protect the occupant, and at the same time, impact energy is absorbed by discharging expanded gas through a vent hole formed in the airbag cushion, impact force transmitted to the occupant at the time of a vehicle collision is effectively absorbed, and as a result, injury to the occupant may be reduced.
Meanwhile, recently, an active vent is used in order to prevent injury to a head or a neck of the occupant from being increased due to an excessive increase in pressure of the airbag when the airbag is operated.
The active vent closes the vent hole when the airbag is deployed, and opens the vent hole by a vent operation signal so as to lower pressure in the airbag. As a result, injury to the head or the neck of the occupant may be reduced by the decrease in pressure in the airbag.
However, because pressure in the airbag is continuously and quickly reduced after the vent hole is opened by an operation of the active vent, relative motion of the head and the neck of the occupant is increased, and as a result, there is a problem in that injury to the neck is increased.